水保所知识产出(1956---)知识库

Grazingprohibitionisaneffectivemeasureinimprovingsoilstabilityandecologicalquality.However,onlyalim-
itednumberofstudieshavebeenpublishedonthedominantfactorsthatimpactsoilaggregatestabilityandtheir
associated effects on nutrient distribution for different size soil aggregates under long-term grazing prohibition
management. In this study, we investigated variation in soil aggregate stability and nutrient distribution charac-
teristics in semiarid grassland sites under different grazing prohibition timeframes (0 years [GP0], 11 years
[GP11], 26 years [GP26], and 36 years [GP36]). Results showed that organic carbon (C) and total nitrogen (TN)
concentrations in soil aggregates decreased at GP11 before progressively increasing and reaching its highest
value atGP36,andthetotal phosphorus (TP)concentration didnot change significantly.Most nutrients accumu-
lated in macroaggregates (> 0.25 mm) under grazing prohibition, and the nutrient stoichiometry in soil aggre-
gates increased after 26 years. Compared to the control (GP0), the mean weight diameter (MWD) value of the
soil stability index increased at GP11 (21.7%) and decreased at GP26 (18.9%). Attenuated total reflection Fourier
transform infrared spectroscopy (ATR-FTIR) also showed that the proportion of stable organic C-related func-
tional groups (i.e., alkene-C and aromatic-C) in macroaggregates were higher at GP11 and GP36 than at GP26.
Furthermore,principalcomponentanalysis(PCA),partialleastsquarespath modeling(PLS-PM),andtherelative
importanceofregressorsallshowedthatglomalin-relatedsoilproteins(GRSP)andnutrientsindirectlyimprovedaggregate stability in semiarid grassland through their influence on the GRSP accumulation potential and nutri-
ent stoichiometry. Generally, after 26 years grazing prohibition had a positive effect on soil aggregate stability
and nutrient accumulation inthesemiaridgrasslandsitesinvestigatedfor this study. Resultsfromthis studypro-
videatheoreticalbasistoselectappropriategrazingprohibition timeframesundergrasslandmanagementinitia-
tives to optimize ecological quality measures in semiarid regions.